In automobiles having automatic transmissions it is desirable if not necessary to prevent starting the engine unless the transmission is in neutral or park position. This invention relates to a switch which is responsive to the position of a transmission part to enable (close) the starting circuit only when the lever is in park or neutral as well as closing the back up light circuit when the transmission is in reverse.
The most relevant prior art is a switch made by Frank Kirsten KG of Germany. The detailed description of the present invention will point up the differences over that switch but at this point it may be stated that both designs require a cam surface controlling engagement of a shorting bar with spaced terminals (busses). In the Kirsten design the cam is a separate insert in a plastic body. The present design eliminates the insert and provides a cam by simply removing the cam surface where indicated by coring the molded plastic body. This reduces the number of parts and increases accuracy of the switching. The shorting bar is provided with a knurled surface which results in a rolling action of the shorting bar when the bar is out of engagement with the busses and results in sliding the bar on the busses.